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1da177e4 LT |
1 | /* |
2 | * JFFS2 -- Journalling Flash File System, Version 2. | |
3 | * | |
4 | * Copyright (C) 2001-2003 Red Hat, Inc. | |
5 | * | |
6 | * Created by David Woodhouse <dwmw2@infradead.org> | |
7 | * | |
8 | * For licensing information, see the file 'LICENCE' in this directory. | |
9 | * | |
32f1a95d | 10 | * $Id: read.c,v 1.39 2005/03/01 10:34:03 dedekind Exp $ |
1da177e4 LT |
11 | * |
12 | */ | |
13 | ||
14 | #include <linux/kernel.h> | |
15 | #include <linux/slab.h> | |
16 | #include <linux/crc32.h> | |
17 | #include <linux/pagemap.h> | |
18 | #include <linux/mtd/mtd.h> | |
19 | #include <linux/compiler.h> | |
20 | #include "nodelist.h" | |
21 | #include "compr.h" | |
22 | ||
23 | int jffs2_read_dnode(struct jffs2_sb_info *c, struct jffs2_inode_info *f, | |
24 | struct jffs2_full_dnode *fd, unsigned char *buf, | |
25 | int ofs, int len) | |
26 | { | |
27 | struct jffs2_raw_inode *ri; | |
28 | size_t readlen; | |
29 | uint32_t crc; | |
30 | unsigned char *decomprbuf = NULL; | |
31 | unsigned char *readbuf = NULL; | |
32 | int ret = 0; | |
33 | ||
34 | ri = jffs2_alloc_raw_inode(); | |
35 | if (!ri) | |
36 | return -ENOMEM; | |
37 | ||
38 | ret = jffs2_flash_read(c, ref_offset(fd->raw), sizeof(*ri), &readlen, (char *)ri); | |
39 | if (ret) { | |
40 | jffs2_free_raw_inode(ri); | |
41 | printk(KERN_WARNING "Error reading node from 0x%08x: %d\n", ref_offset(fd->raw), ret); | |
42 | return ret; | |
43 | } | |
44 | if (readlen != sizeof(*ri)) { | |
45 | jffs2_free_raw_inode(ri); | |
46 | printk(KERN_WARNING "Short read from 0x%08x: wanted 0x%zx bytes, got 0x%zx\n", | |
47 | ref_offset(fd->raw), sizeof(*ri), readlen); | |
48 | return -EIO; | |
49 | } | |
50 | crc = crc32(0, ri, sizeof(*ri)-8); | |
51 | ||
52 | D1(printk(KERN_DEBUG "Node read from %08x: node_crc %08x, calculated CRC %08x. dsize %x, csize %x, offset %x, buf %p\n", | |
53 | ref_offset(fd->raw), je32_to_cpu(ri->node_crc), | |
54 | crc, je32_to_cpu(ri->dsize), je32_to_cpu(ri->csize), | |
55 | je32_to_cpu(ri->offset), buf)); | |
56 | if (crc != je32_to_cpu(ri->node_crc)) { | |
57 | printk(KERN_WARNING "Node CRC %08x != calculated CRC %08x for node at %08x\n", | |
58 | je32_to_cpu(ri->node_crc), crc, ref_offset(fd->raw)); | |
59 | ret = -EIO; | |
60 | goto out_ri; | |
61 | } | |
62 | /* There was a bug where we wrote hole nodes out with csize/dsize | |
63 | swapped. Deal with it */ | |
64 | if (ri->compr == JFFS2_COMPR_ZERO && !je32_to_cpu(ri->dsize) && | |
65 | je32_to_cpu(ri->csize)) { | |
66 | ri->dsize = ri->csize; | |
67 | ri->csize = cpu_to_je32(0); | |
68 | } | |
69 | ||
70 | D1(if(ofs + len > je32_to_cpu(ri->dsize)) { | |
71 | printk(KERN_WARNING "jffs2_read_dnode() asked for %d bytes at %d from %d-byte node\n", | |
72 | len, ofs, je32_to_cpu(ri->dsize)); | |
73 | ret = -EINVAL; | |
74 | goto out_ri; | |
75 | }); | |
76 | ||
77 | ||
78 | if (ri->compr == JFFS2_COMPR_ZERO) { | |
79 | memset(buf, 0, len); | |
80 | goto out_ri; | |
81 | } | |
82 | ||
83 | /* Cases: | |
84 | Reading whole node and it's uncompressed - read directly to buffer provided, check CRC. | |
85 | Reading whole node and it's compressed - read into comprbuf, check CRC and decompress to buffer provided | |
86 | Reading partial node and it's uncompressed - read into readbuf, check CRC, and copy | |
87 | Reading partial node and it's compressed - read into readbuf, check checksum, decompress to decomprbuf and copy | |
88 | */ | |
89 | if (ri->compr == JFFS2_COMPR_NONE && len == je32_to_cpu(ri->dsize)) { | |
90 | readbuf = buf; | |
91 | } else { | |
92 | readbuf = kmalloc(je32_to_cpu(ri->csize), GFP_KERNEL); | |
93 | if (!readbuf) { | |
94 | ret = -ENOMEM; | |
95 | goto out_ri; | |
96 | } | |
97 | } | |
98 | if (ri->compr != JFFS2_COMPR_NONE) { | |
99 | if (len < je32_to_cpu(ri->dsize)) { | |
100 | decomprbuf = kmalloc(je32_to_cpu(ri->dsize), GFP_KERNEL); | |
101 | if (!decomprbuf) { | |
102 | ret = -ENOMEM; | |
103 | goto out_readbuf; | |
104 | } | |
105 | } else { | |
106 | decomprbuf = buf; | |
107 | } | |
108 | } else { | |
109 | decomprbuf = readbuf; | |
110 | } | |
111 | ||
112 | D2(printk(KERN_DEBUG "Read %d bytes to %p\n", je32_to_cpu(ri->csize), | |
113 | readbuf)); | |
114 | ret = jffs2_flash_read(c, (ref_offset(fd->raw)) + sizeof(*ri), | |
115 | je32_to_cpu(ri->csize), &readlen, readbuf); | |
116 | ||
117 | if (!ret && readlen != je32_to_cpu(ri->csize)) | |
118 | ret = -EIO; | |
119 | if (ret) | |
120 | goto out_decomprbuf; | |
121 | ||
122 | crc = crc32(0, readbuf, je32_to_cpu(ri->csize)); | |
123 | if (crc != je32_to_cpu(ri->data_crc)) { | |
124 | printk(KERN_WARNING "Data CRC %08x != calculated CRC %08x for node at %08x\n", | |
125 | je32_to_cpu(ri->data_crc), crc, ref_offset(fd->raw)); | |
126 | ret = -EIO; | |
127 | goto out_decomprbuf; | |
128 | } | |
129 | D2(printk(KERN_DEBUG "Data CRC matches calculated CRC %08x\n", crc)); | |
130 | if (ri->compr != JFFS2_COMPR_NONE) { | |
131 | D2(printk(KERN_DEBUG "Decompress %d bytes from %p to %d bytes at %p\n", | |
132 | je32_to_cpu(ri->csize), readbuf, je32_to_cpu(ri->dsize), decomprbuf)); | |
133 | ret = jffs2_decompress(c, f, ri->compr | (ri->usercompr << 8), readbuf, decomprbuf, je32_to_cpu(ri->csize), je32_to_cpu(ri->dsize)); | |
134 | if (ret) { | |
135 | printk(KERN_WARNING "Error: jffs2_decompress returned %d\n", ret); | |
136 | goto out_decomprbuf; | |
137 | } | |
138 | } | |
139 | ||
140 | if (len < je32_to_cpu(ri->dsize)) { | |
141 | memcpy(buf, decomprbuf+ofs, len); | |
142 | } | |
143 | out_decomprbuf: | |
144 | if(decomprbuf != buf && decomprbuf != readbuf) | |
145 | kfree(decomprbuf); | |
146 | out_readbuf: | |
147 | if(readbuf != buf) | |
148 | kfree(readbuf); | |
149 | out_ri: | |
150 | jffs2_free_raw_inode(ri); | |
151 | ||
152 | return ret; | |
153 | } | |
154 | ||
155 | int jffs2_read_inode_range(struct jffs2_sb_info *c, struct jffs2_inode_info *f, | |
156 | unsigned char *buf, uint32_t offset, uint32_t len) | |
157 | { | |
158 | uint32_t end = offset + len; | |
159 | struct jffs2_node_frag *frag; | |
160 | int ret; | |
161 | ||
162 | D1(printk(KERN_DEBUG "jffs2_read_inode_range: ino #%u, range 0x%08x-0x%08x\n", | |
163 | f->inocache->ino, offset, offset+len)); | |
164 | ||
165 | frag = jffs2_lookup_node_frag(&f->fragtree, offset); | |
166 | ||
167 | /* XXX FIXME: Where a single physical node actually shows up in two | |
168 | frags, we read it twice. Don't do that. */ | |
169 | /* Now we're pointing at the first frag which overlaps our page */ | |
170 | while(offset < end) { | |
171 | D2(printk(KERN_DEBUG "jffs2_read_inode_range: offset %d, end %d\n", offset, end)); | |
172 | if (unlikely(!frag || frag->ofs > offset)) { | |
173 | uint32_t holesize = end - offset; | |
174 | if (frag) { | |
175 | D1(printk(KERN_NOTICE "Eep. Hole in ino #%u fraglist. frag->ofs = 0x%08x, offset = 0x%08x\n", f->inocache->ino, frag->ofs, offset)); | |
176 | holesize = min(holesize, frag->ofs - offset); | |
177 | D2(jffs2_print_frag_list(f)); | |
178 | } | |
179 | D1(printk(KERN_DEBUG "Filling non-frag hole from %d-%d\n", offset, offset+holesize)); | |
180 | memset(buf, 0, holesize); | |
181 | buf += holesize; | |
182 | offset += holesize; | |
183 | continue; | |
184 | } else if (unlikely(!frag->node)) { | |
185 | uint32_t holeend = min(end, frag->ofs + frag->size); | |
186 | D1(printk(KERN_DEBUG "Filling frag hole from %d-%d (frag 0x%x 0x%x)\n", offset, holeend, frag->ofs, frag->ofs + frag->size)); | |
187 | memset(buf, 0, holeend - offset); | |
188 | buf += holeend - offset; | |
189 | offset = holeend; | |
190 | frag = frag_next(frag); | |
191 | continue; | |
192 | } else { | |
193 | uint32_t readlen; | |
194 | uint32_t fragofs; /* offset within the frag to start reading */ | |
195 | ||
196 | fragofs = offset - frag->ofs; | |
197 | readlen = min(frag->size - fragofs, end - offset); | |
198 | D1(printk(KERN_DEBUG "Reading %d-%d from node at 0x%08x (%d)\n", | |
199 | frag->ofs+fragofs, frag->ofs+fragofs+readlen, | |
200 | ref_offset(frag->node->raw), ref_flags(frag->node->raw))); | |
201 | ret = jffs2_read_dnode(c, f, frag->node, buf, fragofs + frag->ofs - frag->node->ofs, readlen); | |
202 | D2(printk(KERN_DEBUG "node read done\n")); | |
203 | if (ret) { | |
204 | D1(printk(KERN_DEBUG"jffs2_read_inode_range error %d\n",ret)); | |
205 | memset(buf, 0, readlen); | |
206 | return ret; | |
207 | } | |
208 | buf += readlen; | |
209 | offset += readlen; | |
210 | frag = frag_next(frag); | |
211 | D2(printk(KERN_DEBUG "node read was OK. Looping\n")); | |
212 | } | |
213 | } | |
214 | return 0; | |
215 | } | |
216 |